The long-term goal of the proposed studies is to obtain useful information on the functional organization of the putamen using single unit recording techniques in monkeys trained to make operant motor responses. As a first approach to this problem a study will be made of the movement-related activities of a unique cortical efferent system which provides a major source of input to the putamen, viz. corticostriatal neurons, which originate in motor cortex. By defining activities of corticostriatal neurons in relation to variables of motor output as well as tactile and proprioceptive inputs to these cells, and comparing these properties with those of another cortical efferent system, the pyramidal tract neurons, the unique functional properties of the corticostriatal neuron efferent system can be determined. In monkeys trained to perform discrete movement tasks (flexion-extension of wrist) single unit recording studies will be made of neurons in the putamen of further characterize properties of clusters or arm movement-related neurons which occur in intermediate regions of the putamen. By defining activities of putaminal neurons in relation to variables of motor output, responses to passive sensory stimulation and intracortical microstimulation of motor cortex, and then comparing the properties of putaminal and corticostriatal neurons, it is hoped that further insight into the role of motor cortex and putamen in the control of voluntary movement can be gained.